Thirty-six percent of the mentally ill smoke, compared with 21 percent of those without mental illnesses.

Among the mentally ill, there is a higher incidence of smoking among younger adults, Native Americans, Alaskan natives, the poor and the less educated.

The percentage of smokers among the mentally ill varies greatly among the states, from 18.2 percent in Utah to 48.7 percent in West Virginia. In Illinois, 38 percent of people with mental illnesses smoke.

The respondents were from the Substance Abuse and Mental Health Services Administration's 2009-11 survey of 138,000 people 18 and older.

The report defined "any mental illness" (AMI) as having a "diagnosable" mental, behavioral or emotional disorder in the last year. It excluded people with developmental or substance abuse disorders and the institutionalized. Respondents reported their illnesses according to criteria they were given from the Diagnostic and Statistical Manual of Mental Disorders.

There are several reasons for the discrepancies, said Dr. Tim McAfee, director of the CDC's Office on Smoking and Health.

"Part of it is biological," McAfee said. "Nicotine is a mood-altering stimulant, so it can help mask negative moods. It's a temporary way to feel less anxious, for example. Then it becomes a vicious cycle because you are less able to quit smoking because withdrawal symptoms can make you more anxious."

Another reason is "people with AMI are more likely to have a lower socioeconomic status and less likely to be educated about the dangers of smoking," McAfee said. "This story will be in major newspapers, for example, but it won't reach the people who are not reading newspapers."

The geographic differences in smoking rates are because of varying socioeconomic demographics, access to health care, cigarette sales taxes and state policies.

"Some states are very aggressive with anti-smoking campaigns," McAfee said. "Others do nothing."

To educate the community about the dangers of smoking, the CDC recommends changes at the federal, state and local levels.

The federal government can help, the report said, by funding state and local smoking cessation programs. States can enforce no-smoking rules at state mental health facilities.

At the local level, the CDC recommends all mental health facilities become smoke-free zones and include smoking cessation programs. And, they should quit dispensing cigarettes as rewards for progress, a practice McAfee said still occurs.

The CDC urges mental-health professionals to screen patients for smoking, refer them to resources such as smokefree.gov and incorporate cessation programs into their other programs.

Smokers can help themselves, the report said, by making the decision to quit smoking, avoiding secondhand smoke and supporting others who are trying to quit.

It's time to dispel the myth that the mentally ill don't want to quit and can't quit, McAfee said.

"Like people without mental illness, (the mentally ill) benefit from stop-smoking programs," he said.

It's never too late to quit, McAfee added.

"Previous studies have shown if you smoke, you cut 10 years off your life," McAfee said. "But if you quit before you're 35, you can gain most of that back. Even if you quit later, you can reduce your risk of heart attack, stroke and cancer."

Although smoking is down in the general population, it's the leading cause of preventable disease and death, the CDC said, and leads to 443,000 premature deaths a year.

"'Preventable' is the key word," McAfee said. "It is one of most dramatic changes you can make regarding your health. If you have AMI and smoke, you are more likely to die from smoking than from your mental illness."